Internal combustion motor



July 19, 1938. 11c, MARSHALL 2,124,492

INTERNAL COMBUSTION MOTOR Filed May 19, 1936 2 Sheets-Sheet l July 19 193s c, ARSHALL 2,124,492

INTERNAL COMBUSTION MOTOR Filed May 19, 1936 2 Sheets-Sheet 2 Patented July 19, 1938 UNITED STATES PATENT OFFICE Application May 19,

8 Claims.

This invention relates to certain improve- 7 ments in internal combustion motors, and more particularly concerns the automatic control of themotor intake vacuum and fuel'mixtures in accordance with motor operating conditions; and the nature and objects of the invention will be readily apparent to and understood by those skilled in the art in the light of the following explanation and detailed description of the ,accompanying drawings illustrating what I at present believe to be the preferred forms or mechanical expressions of my invention from among various other forms, embodiments, arrangements, combinations and constructions of which the invention is capable within the broad spirit and basic scope thereof.

The invention is concerned with and directed to the problems of controlling the vacuum cre-' ated in motors or engines of the internal combustion types, and in concurrently varying the fuel mixture for such motors, in accordance with the varying conditions under which the motor operates, for the purpose of materially increasing the efficiency of a motor by reducing the fuel waste and power loss resulting from high motor vacuum and over-rich fuel mixtures which are encountered under certain conditions of motor operation. While not so limited or restricted, the invention is of particular utility in connection with internal combustion motors of automotive vehicles, because it is under the operating conditions encountered by such motors that the disadvantages and inefficiencies resulting from high vacuum conditions and over-rich fuel mixtures are encountered in a very high degree.

One of the features of the invention resides in the provision of an apparatus or device for combination with an internal combustion motor and capable of automatically functioning or operating to establish the different allowable maximum vacuums for the several ranges of motor operation respectively and to automatically prevent the motor vacuum from exceeding such maximums during the operation of the motor in the respective ranges by the admission of air to the motor intake; while the fuel mixture is simultaneously varied by such air admission in accordance with such vacuum control.

Another feature of the invention is found in the utilization of the force exerted by the suction effect of the motor vacuum to automatically assist in the establishment and maintenance of the different allowable maximum .vacuum magnitudes for the respective portions of the motor operating range; and further in the 1936, Serial No. 80,620

control of the application of such vacuum force by and in accordance with the motor operating conditions corresponding to the positions of the motor throttle valve for the different portions of the operating range of the motor.

A further feature and characteristic of the invention is found in the controlled application of the suction force of the motor intake vacuum to overcome or oppose the force of such vacuum which is simultaneously applied to an air admission valve in a manner continuously tending to open such valve, with the result that for and during a certain portion of the motor operating range the air valve is maintained closed against a'motor vacuum of greater magnitude than normally required to open the valve when the opposing vacuum force is removed; such force which opposes air valve opening being removed for normal operation of the valve during the remaining or other portions of the motor operating range. V

A more specific feature of the invention is presented by an embodiment of apparatus in which an air valve of a certain area is maintained closed against the direct suction effect on such valve area of motor intake vacuum magnitudes below a predetermined vacuum magnitude by the application of a closing force to such valve, and a suction operated piston of a predetermined area relative to the valve area is provided for actuation by the suction force of the motor intake vacuum to apply an additional closing force opposing opening of the air valve byintake vacuum below a magnitude that is greater than the valve opening maximum vacuum when such additional closing force is removed, the valve being openedagainst the combined closing forces by a vacuum of or greater than the predetermined maximum.

A further more general object of the invention is to provide a practical design of apparatus embodying the foregoing features and characteristics, which will be positive and eflicient in operation and results, and one which lends itself readily to application to or incorporation in an internal combustion motor, while being of relatively low initial cost and requiring a minimum of attention and upkeep in operation and use.

'With the foregoin general objects, features and characteristics in view, as well as certain others that will appear from the following description, my invention consists in certain novel features in design and in combinations and arrangements of parts, as well as in the mode or method of operation-all as will be more fully and particularly referred to and specified hereinafter.

Referring to the accompanying drawings, in which similar reference characters refer to corresponding parts throughout the several figures thereof:

Fig. 1 is a view in side elevation of portions of an internal combustion engine or motor of an automotive vehicle, including the motor fuel intake line, intake manifold, throttle valve and a portion of its operating mechanism, with a prefered form or embodiment of apparatus providing the air valve unit of the invention installed and mounted on the motor in operative relation and connection therewith; the motor throttle valve and its operating mechanism being shown as in normal closed or motor idling position.

Fig. 2 is a vertical longitudinal section through the valve unit and its operating an d control means of Fig. 1, the air admission valve being shown in closed position held against opening by the combined forces exerted thereon by theupper spring and the vacuum operated piston.

Fig. 3 is a view similar'to Fig. 2, but showing the air admission valve in raised open position against the force of the closing spring and with the vacuum operated piston released from the suction force of the intake vacuum and inactive to apply forces to' the valve opposing opening thereof.

Fig. 4 is a transverse horizontal section through the valve unit, taken as on the line 44, of

Fig. 2.

An automatically operated air admission valve unit embodying and including the principles and various features of my present invention, is adapted to and intended for application to and use with internal combustion motors generally, but such a unit is primarily adapted to meet the operating conditions encountered with the internal combustion motors or engines of automotive vehicles, especially motor vehicles of the road'types, or automobiles. Hence, I have'in the present instance, as an example for'the purpose of describing and explaining the principles and features of the invention, selected an adap tati'on or embodiment of the invention which is designed for application to and use with 'a typical motor of a motor vehicle of the road type. Such motors are more or less standard or con Ventional and familiar to and well understood by those skilled in the art, and I have considered it only necessary in the accompanying drawings to illustrate those parts or elements of a typical automobile motor with which the apparatus forming an air valve unit of the invention is associated or cooperates in the, operation and use of the unit.

As representative of a typical and well known motor vehicle internal combustion engine or motor, I have illustrated in Fig. 1 of the accompanying drawings, the intake manifold M of the motor connected'by the fuel mixtureintake line L with the carbureter C, through which the fuel mixture is drawn from the carbureter into the usual combustion chambers of the motor cylinders by suction force created in the manifold and intake line by the motor pistons, all in, the usual ,and well known manner. The usual motor throttle or butterfly valve V is shown bydotted lines in Fig. 1, mounted in the motor intake line L for rotation to open and close such line to control the flow of fuelmixture to the motor and thereby control the'operation and carbureter and "or 2 inches on a vacuum gauge.

performance of the motor. The position of valve V as shown in Fig. 1 is the usual or normal valve closed or idling setting of the valve. The valve V is actuated and controlled by the driver of the motor vehicle, through the medium of a throttle valve operating mechanism that includes the rotary shaft I coupled to the valve V, and the link 2 pivotally connected between and operatively coupling an arm 3 on shaft I and an end of the rocker arm 4. The arm 4 is suitably coupled with and actuated by the usual driver operated foot and/or hand controlled accelerator or the like member (not shown) in the conventional or any desired manner.

The motor throttle valve V' and its driver actuated operating mechanism l2-3-4, are shown in Fig. 1 of the drawings with the throttle Valve in its normal so-called closed position or idling setting for idling operation of the motor. The throttle valve V is rotated or swung to open positions from the illustrated idling position, by upward swinging of arm 4, which through link 2, rocks arm 3 and rotates the Valve to opened positions for increased flow of fuel mixturefrom carbureter C to the intake manifold M and the motor, to accelerate and increase the speed and power of the motor. The valve is rotated from open positions toward closed or idling positionto decrease fuel flow to the motor and decrease the motor speed and power, by reverse movements of the valve operating mechanism, that is, arm 4 is swung downwardly with resulting movements of links 2 and 3 andshaft l to close the valve.

With the throttle valve V in its motor idling or closed setting of Fig. 1, it was found that the particularmotor of the example hereof, .devel-r oped a vacuum of the order of approximatelyZO inches on a vacuum' gauge, in the intake line L, manifold M and the motor,,against which the idling motor must operate. Such a vacuum condition with the vehicle at rest and the motor idling is not, however, a serious operating condition or one that contributes largely to substantial fuel waste and power loss, particularly when it is considered that a motor and its fuel mixture supply must be adjusted for an efficient the example hereof, a vacuum in the intake of' the order of approximately 20 inches on a vacuum gauge, was found to exist. motor throttle valve V is further opened to increase the speed of the motor and vehicle, the vacuum in the intake drops or decreases rapidly with the opening of the throttle valve, and if the motor throttle valve is opened to maximum open position or full throttle, the vacuum in the If then the intake drops or decreases to a very low degree corresponding to an order of approximately 1 However, as the motor and vehicle accelerate by the opening of the throttle, the driver naturally slowly closes the throttle with the result that the vacuumin then acting partially as a pump, and this increasing vacuum will attain the very high degree of the order 'of 25 to. 26 inches on a vacuum gauge. brought to its idling position under such condi- 1 tions with the vehicle moving at the higher rates of speed, there-is developed this very high degree 1 the otherdisadvantages hereinbef'o-re referred to,

due to the high vacuum conditions in the motor intake, are encountered in such rage of operation.

Following and applying the principles on which my invention is based, 1- provide for an automatic controlof the motor intake vacuum conditions to reduce the high vacuum,- and concurrently with and as a result of such reduction I obtain a dilution of the fuel mixture, in the motor intake during and throughout the ranges of motor vehicle driving speeds at which such high vacuum is mainly encountered. I accomplish this vacuum control through the medium of an air admission valve in the motor intake line L intermediate the carburetor C and the motor intake manifold M to the motor, which valve is controlled automatically by forces applied thereto as the differential between the force of the intake vacuum acting to open the valve, and predetermined forces of different magnitudes selectively and independently applied to the valve to close it, the application of such independently applied forces being synchronized with and according to the setting or position of the motor throttle valve V. Such an intake air admission valve may, as in the example hereof, be embodied in a valve unit I0 which is coupled into communication with the intake line L by the conduit or air pipe II, as clearly shown in Fig. 1 of the drawings, for discharging air into the intakeline L to break down or decrease the magnitude of a condition of vacuum therein, and at the same time dilute or reduce the richness of the fuel mixture drawn or sucked up by the motor through the line from the carbureter C.

In the particular form and embodiment of the valve unit Ill illustrated herein as an example, such unit includes a main casing I2, preferably, although not essentially, of generally cylindrical form, having an open internally threaded lower end I4 and a decreased diameter upper end portion I5 terminating in the head I6 (see Fig. 2), providing a vertical boss having an internally threaded axial bore l6a there-through. The casing or housing I2 is formed with a horizontal laterally extended air discharge outlet I1 from one side thereof having a relatively large internal diameter and internally threaded at its outer end for coupling to the air conduit or pipe II to place the interior of easing I2 into communication with the motor intake line L.

The lower end of the casing I 2 of the valve unit Ill receives a valve seat forming and air intake member I8 that is threaded into the casing and provides a depending vertically disposed air intake tube I 9 with the bore of the tube I9 continued axially through member I8 and opening at its upper end into the chamber or space formed within the casing I2. I91; of the depending tube or casing I9 is enlarged or belied to provide'an increased internal- If the motor throttle valve V is then The lower portion diameter for the air passage therethrough, and i such increased diameter portion I911. is internally threaded at I9'b. The upper side or face of member I8 within the casing I2 has the edge thereof around the air-inlet passage therethrough beveled to provide a valve seat 26 for receiving the air admission valve to be hereinafter described.

Within the-air chamber formed by the valve unit casing I2, for cooperation with the valve seat 20' to open and close the air inlet passage to the chamber, the vertically movable or reciprocal air admission valve 22 is mounted for automatic operation in accordance with the principles of the invention, The air valve 22 in the present example, is mounted in horizontal position on the upper side of the member I8 over the upper inlet end of the air passage through member I8, and is provided with the annular beveled valve face 23 there-around for engaging and seating on valve seat 20 with the valve in lowered, closed position (see Fig. 2). The valve 22 has a diameter greater than the maximum diameter of valve seat 20 and provides the annular flange 24 therearound which extends over the upper end or edge of member I8. The valve 22 is also provided with a depending axial body portion 22a that includes the spaced vertical ribs 22b extending radially therefrom in diametrically opposite pairs (see Fig. 4), which body and ribs extend down. into the cylindrical bore forming the air inlet passage through member I8, with the ribs 22b in sliding engagement with the passage walls to form a guiding and centering structure. for the valve in its vertical reciprocation between opened and closed positions.

The air admission valve 22 of the valve unit I0 is normally forced downwardly and maintained in seated and closed position as shown in Fig. 2, by a force exerting member or unit, such as the expansion coil spring 25, mounted above the valve. In the particular arrangement here shown, the valve 22 is formed with an axial bore 220 extending downwardly therethrough from the upper side of the valve, and a rod 26 is fitted into bore 220 and supported therein by a flange 2611 on the rod Which engages and rests upon the upper surface or face of the valve, as will be clear by reference to Fig. 2 of the drawings. The rod 26 extends upwardly through the casing I2 and is slidably received at its upper end in a spring force adjusting tube or member 21 which is externally'threaded and screwed down through the internally threaded bore. I6a of the end boss I6 of the casing upper end portion I 5. The upper end of adjusting tube 21 is formed with the head 21a, and a set or look nut 21b is provided on the tube between the head and the upper end face of boss I8 for securing the tube in an adjusted position (see Fig. 2 of the drawings). A cover or cap 28 is removably threaded onto the externally threaded boss I8 of casing I2 and encloses and covers the upper end of the adjusting sleeve 21.

The valve spring 25 is mounted around rod 26 within the casing chamber and is held between vertically spaced plate members or washers 29. and 3B. The lower of these washers 29 rests upon a spacer 29a which is supported in position on the rod by an enlargement 26b of the rod above the rod flange 26a. The upper spring holding washer 30 is slidably mounted on the rod and is held against upward movement thereon by the lower end of spring force adjusting tube'2'l Thus, the spring 25is held between the lower washer 29. and upper washer 30, preferably under initial 1 22 and rod 26 are free to move upwardly to unseat the valve to open position by compressing spring between plates or washers 29 and 3|]. The initial compression and force exerted by the spring on the valve can be adjusted by screwing tube 21 downwardly to increase spring force, and

upwardly to decrease the force exerted on the valve by thespring.

In accordance with a further feature of my invention, I make provision for the application of valve closing forces to the valve 22 in addition to the force normally constantly applied by the valve closing spring 25, but such additional closing force is only applied under certain conditions of motor operation as determined by certain motor throttle valve'positions or settings. Such additional valve closing force is obtained from the suction force of the motor intake vacuum, and in carrying out this feature of the invention I have ;in the present example provided a cylinder 30 in which a piston 3| is reciprocally confined, the cylinder being placed in communication with the motor intake at one side of the piston, and the piston being coupled with the air admission valve 22.

For instance, the cylinder 30 may, as in the example hereof, be formed of bronze or other suitable material with one end thereof closed, as by ahead 33a which may be welded or otherwise secured, and the opposite end thereof open and externally screw threaded. The cylinder is mounted as an element of the valve unit by screwing the upper open end thereof into the lower enlarged end |3a of tube I9, so that the cylinder forms a depending continuation of tube H3 in substantial axial alinement therewith, with the lower end of the cylinder closed by head 30a, as will be clear by reference to Figs. 2 and 3 of the drawings. The cylinder 30 is provided with a series of spaced air inlet openings or ports 32 through the side wall thereof in the upper portion of the cylinder adjacent the lower end of tube portion |9a. These ports 32 provide the medium by which air is drawn into the valve unit and passes upwardlytherethrough into casing i2 and pipe when the air admission valve 22 is in raised and open position.

The piston 3| may preferably, although of course not essentially, be formed of aluminum and is provided with a suitable peripheral groove therearound to receive a usual type of split sealing ring 3|a by which the piston is maintained in substantial though not absolute sealing engagement with the wall of cylinder 39. The piston sealing ring 3|a is preferably in the example hereof, of very light tension and may be formed of cast iron. A piston rod 33 is provided for piston 3|, being secured to the piston in any suitable or desired manner, and extends a distance upwardly from the piston through cylinder 30 and into the lower end portion |9a of tube IS. The piston rod 33 is operatively coupled with the air admission valve 22 in order that downward movement of piston 3| in cylinder 30 will apply downwardly acting closing forces to valve 22 in addition to the closing forces applied by spring 25. Such connection of the piston with the valve is carried out in the present example by securing a rod 34 in an axial bore in the valve body 22a in position depending from such body to the'upper end of the piston rod 33 in substantial axial alinement with the piston rod. The adjacent ends of the piston rod 33 and depending valve carried rod 34 are operatively coupled by a pivotal connection 35 which functions in effect as a universal connection in order to compensate for any nonalignment between, cylinder 30, tube I9 and valve 22, and prevent any tendency of the piston and associated parts tobind during vertical reciprocation thereof in operation.

The lower closed end or head 30a of cylinder 30 is in this instance provided with a pair of spaced and internally threaded bores or openings therethrough (see Fig. 4), one of which receives a closure plug 36 (see Fig. 3) and the other of which receives the end of a pipe line such as provided by the elbow 31 in the specific example hereof. With the cylinder so mounted and arranged the piston 3| is positioned spaced a distance above cylinder head 30a when valve 22 is in lowered closed position, as shown'by Fig. 2,

while upward movement of the valve 22 to raised and open position, moves piston 3| but a slight distance to the position thereof as shown in Fig. 3.

Referring now to Fig. 1 of the drawings, with the valve unit I 0 mounted on the motor and connected with the intake manifold L by the pipe I for discharge of air from the unit into the manifold, the cylinder 30 is placed in communication with the intake manifold in such a manner that the suction effect of the manifold vacuum can be applied to piston 3| to cause the latter to apply closing forces to the air admission valve 22. For example a tube 38 is connected to and in com munication with the motor intake manifold at 38a and extends to and is placed in communication with the cylinder 3|] below piston 3|,through the elbow or coupling member 31. A valve unit 48, which as in the example hereof may be of the conventional and well known barrel or plug type, is interposed and coupled into the tube or pipe line 38 for the purpose of shutting off or opening the line and cylinder 30 from and to communication with the motor intake line L. The valve stem or operating shaft a (see Figs. 2 and 3) is provided with an actuating arm 4|, which in this instance extends in a generally horizontally disposed position when valve 40 is rotated to open position, as shown in Fig. 1 in particular.

The valve 40 is operatively coupled and associated with the actuating mechanism for the motor throttle valve V, and as shown in Fig. 1, such coupling may be provided by an adjustable length link or push-pull rod 42 pivotally connected to and coupling the end of arm 4 with the end of valve actuating arm 4|, so that valve 4|] is opened and closed in accordance with the position or setting of the motor throttle valve V, that is to say, in accordance with the motor operating conditions of speed and power.

In the example hereof, the arm 4| and rod 42 are set so that with the motor throttle valve V in closed or'motor idling position, as shown in Figs. 1 and 2, the valve 4|] in line or tube 38 is open or partially open, and the linkage is such that upon swinging of arm 4 to move the throttle valve V to opened positions to increase the, speed and power of the motor, the valve 40 remains parcommunication with tube 38 and the'intake line 'L. The opened position of the throttle valve V at which the valve 40 is actuated to closed position may be determined by adjustment in the may be adjusted and determined. Similarly, for

purposes of adjustment and relative setting of valve 4|), the push-pull rod 42 is made adjustable as to length to thereby adjust thelposition of arm 4| relative to arm 4.

The valve unit of the particular example illustrated and specifically described herein,is generally adapted to use with automotive vehicle motors of medium and large size, and I have found in actual construction and operation of such a unit that satisfactory and eflicient results are obtained with the intake to the motor manifold formed by apipe or conduit of approximately one (1) inch diameter, and a valve seat 20 of member I8 of the unit also having a diameter of approximately one (1) inch. The area of the air admission valve 22 may be approximately one inch, while the diameter of the vacuum suction operated piston 3| is accordingly approximately one andone-sixteenth (11 inches. The valve closing spring 25 of the example now referred to has a maximum force corresponding or substantially equivalent to a vacuumtforce represented by approximately ten ('10) inches on a vacuum gauge. This spring 25 mounted as herein illus-' tratecl'is adjustable by member-21 -from its maximum compression to exert the above maximum" force, down to a condition of zero :force, that is, a condition fully expanded.

With the motor of Fig.1, and with the valve unit l0 having the construction described and mounted and connected as shown, in operation of the motor with the throttle valve V in idling position and the vehicle at rest, the valve 40 in the tube 38 is open or partiallyopen. As, with the 'motor of the given example there is'afound to be an intake vacuum of. the order of approximately 18' to 20 inches on a vacuum gauge, this vacuum condition creates a suction force acting through tube 38 and in cylinder 30 beneath piston 3|, with the result that the piston is drawn or sucked downwardly to the position shown in Figs. 1 and 2, to hold air va1ve'22-in closed position onits 'seat'until a force of greater magnitude acts on the valve to raise it and raise the piston againstsuch suction force. Now; in the illustrated example, the'valve closing-spring 25 is adjusted to exert a closing force 'on valve 22 corresponding'to-a force equal tocapproximately inches of vacuum, that is, I establish a relatively constant valve closing force to maintain the valve closed against'an intake vacuum up to a maximum of five (5) inches. The relative diameters of piston SI and valve 22 are such that with valve 40 partially opened a required amount and a vacuum of the order of 20 inches in the motor intake, there will be established a-vacuum' of at least the order of inches in the cylinder acting to draw piston 3| and valve 22 downwardly. Hence, with thesec'onditions prevailing, the valve 22 will be maintained closed against a vacuum of a maximum of the order of inches, so that when the intake vacuum exceeds such maximum the upwardly acting force on the area of valve 22 will overcome the downwardly acting forces of spring 25 on the suction on piston 3|, and the valve 22 will open to admit air to intake line L and break down the vacuum with simultaneous .fuel mixture dilution.

At this point attention is directed to the fact that in installing and adjusting a valve unit In 'on a motor there are three major adjustments. First, the force exerted by valve closing spring 25,;

which is adjusted and set by member'Z'I. Second,

the length of connecting rod or link 42 betweenarm 4| and arm 4, which determines the degree or extent to which valve 40 is opened. Third, the distance between valve stem or shaft 40a and the point of pivotal connection between arm 4| and rod 4m, which in this'instance may be selected by :employing the desired bore of the series of bores 4|a for'attaching rod 42 to arm 4|. This adjustment determines the range of throttle valve movement during which valve 4|] remains in partially opened position, that is, the predetermined open position of'the throttle valve at which valve 40 closes.

The vacuum condition in the cylinder is determined after installation by removing plug 36 and attaching a vacuum gauge into communication with cylinder 3|]. After takingthe necessary readings from the vacuum gauge the various adjustments are made as required to obtain the proper degree of opening of valve and the posi- 'tion' -of closing thereof, and the vacuum gauge is then removed and plug 36 reinserted to close and seal up the cylinder 30;

Referring again 'to the operation of the unit when installed and adjusted as indicated above, with the motor throttle set for motor idling,

valve 40 is open'and there is a total'closing force exerted on valve 22 by the suction force of the intake vacuum onpiston 3| and the 'force exerted by valve closingspring 25, to maintain the'valve 'closed during normal idling with the vehicle at rest against the intake vacuumio'f the order of 18 to 20 inches, but if the vacuum exceeds such maximum, then the suction force acting at the upper side of valve 22 in an upward direction will overcome the'closing forces and raise the valve to open position.

As the motor throttle valve V is opened fromidling position and until the valve reaches a pre-:

determined opened position, say a position corresponding to a motor speed of the order of 600 R. P. M., the idling conditions prevail and the air admission valve '22 is maintained closed by the combined forces exerted thereon by spring 25 and the downwardly sucked or drawn piston 3|, and the valve will be maintained closed until a vacuum of greater than 18 to 20 inches rod 42 to close the valve 40 and thereby shut off cylinder 30 from intake line L, so that, the vacuum suction condition in cylinder 30 is destroyed and the piston 3| is released with the down- =wardly acting 'force exerted thereby on valve 22 removed. Thereupon the air admission valve is only held closed and'seated by the force exerted vthereon by the spring 25, and this condition prevailsfromthe predetermined opened position of throttle valve-V throughout the range to maximum or full open position.

"When the piston 3| is released from the vacuum suction force and is inactive to merely move with 'valve 22, I have-found that there is usually suflicient leakage past the piston to permit of sufliciently free reciprocation of the piston in the cylinder. However, if desired a suitable small vent (not shown) may be provided in the lower end of cylinder 36, or preferably in the elbow 3'! to eliminate resistance topiston movement, as will be'readily understood. The force exerted by the spring 25 is of a magnitude to maintain valve 22 closed against a 10 suction force acting thereon to open the valve, established by a motor intake vacuum of the order say of 5 inches on a vacuum gauge, and such vacuum maximum is substantially:maintained as 'a constant throughout the motor operatingrange during which spring 25 is alone active in applying valve'closing' force. Hence, with the motor ,throttle valve V in open positions and the piston 3| inactive to apply valve closing forces, the air valve 22 is automatically opened when the intake vacuum exceeds the order of approximately 5 inches; and air is admitted from the inlet tube l9 past'valve 22 and through pipe H into the intake line L. This admitted air of course breaks down the vacuum and also dilutes the fuel mix- 25 ture being drawn from the carbureter C, and upon the decrease in vacuum spring 25 forces valve 22 back to closed position on seat 20, so that further air admission is stopped. As a motor vehicle operating in the range from around 20 M. P. H; and higher, develops an intake vacuum of an order above 5 inches, with the air valve unit of 'the examplehereof, the intake vacuum through this range is automatically maintained at or below the order of 5 inches, by '3 the opening of valve 22 against the force of spring 25 whenever the vacuum increases above the indicated allowable" maximum. Thus, by the operation of the motor under suchreduced in- ;takewacuum conditions'the power is increased with areduction in motor'wear, while asubstantial reduction in'fuel consumption is attained together with more perfect combustion and a reduction in the carbon conditions in the motor and exhaust lines. v 4, With the motor operating in the range at which 'the air valve 22 is controlled by the force of the spring 25 solely, of course, upon rapid acceleration by wide opening of throttle valve V, the inftake vacuum reduces rapidly and the valve 22 I remains closed, but as the desired rate of speed is attained the throttle valve is slowly closed and theintake vacuum rapidly builds up until the allowable maximum determined by the force of f spring 25 is reached, whereupon valve 22 is auto- 15 matically opened and'air is admitted to the intake to break down the vacuum and maintain it-at or below the allowablemaximum. The air so admitted to'the' intake line dilutes the fuel mixture to eifect the saving offuel and to reduce overcharging with fueland fouling the motor.

/ When the throttle valve V is closed to idling position, as shown in Fig. 1 with the motor vehicle coasting, as by deceleration from' higher speed, or in coasting down grade with motor 5 idling, immediately the throttle eperating mechanism reaches a position for the predetermined :throttle valve'settingor' partially opened position a't'which valve 40 in line 38 is opened, the intake vacuum draws piston 3| down or exerts a down- 7 wardly' acting force thereon, which is applied as a' closing force to valve 22 by rods 33-44, so that the allowable maximum vacuum intake is increased, in the specific examplehereof, to the order of 20 inches. 'With the vehicle coasting '55 and-the motor idling, the motor is functioningas a pump anda condition of very high vaeuum will 'be established in the motor'intake line, but the combined closing forces of spring 25 and piston 3| applied to valve 22 will not permit the vacuum to exceed the allowable maximumof say of the fuel mixtureis maintained, as well as an ample degree of motor vacuum for vehicle b-rak- 1 ing effect, while the effects of the normal very high vacuum under such operating conditions are eliminated.

It may be here pointed out that under operating conditions of the higher speed range rep- 2 resented by the motor throttle positions between the predetermined throttle open positions and the maximum open position, with the sole valve closing force exerted by spring 25 to maintain a relatively low maximum vacuum, such as the v 5 inches of the present example, then inthe event that air valve 22 should admit too much air at any time for perfect combustion, the motor would tend to slow up and the operator would open the motor throttle to maintain the desired speed. Immediately the throttle is opened the vacuum in theintake will be broken down below the maximum and the air valve 22 will close under the action of spring 25 and the fuel mixture richness will'be restored for propercombustion.

Thus, with an air' valve unit embodying the. principle's'of my invention, mounted a'nd;.connected' in operative association with the motor of an automotive vehicle, the motor is operatedaautomatically under reduced intake vacuum condi :4

mum allowable vacuum is increased by the ad- .5

ditional valve closing force derived 'from'the mo- 1 tor vacuum and applied through the medium of the suction actuated piston 3I.=The maximum vacuum condition permitted in this range may preferably be the vacuum condition obtained:;55, with motor idling and the vehicle at rest, as in the specific example hereof. -Under operating conditions with the motor in such lowerspeed range any increase in'vacuum opens'the .airadmission valve to break downthe vacuum to or go below the allowable maximum; 1

It will be evident that various changes, modifications, variations, substitutions, eliminations, and additions might be resortedto without departing from the spirit and scope of my invention, and hence, I do not desire tov limit myself in all respects to the exact and specific disclosures hereof. W vWhat'I claim is:'

1. In combination with an internal cbmbus- T tion motor including, an intake line, a throttle valve and actuating mechanism for the valve, a

normally closed air'valve for opening to admit air into the intake line to prevent increase of motor vacuum, means continuously applying a 75 'force to said air valve of a'magnitude to maining forces of said means by a vacuum of greater magnitude than the predetermined maximum vacuum, and said vacuum operated means operatively coupled with the throttle valve mechanism and actuated thereby to be rendered inactive for a portion of the operating range of the throttle valve.

2. In combination With'an internal combustion motor including the motor intake line, throttle valve and its actuating mechanism, a normally closed air valve for opening by thesuction force of the motor vacuum to admit air into the motor intake line to prevent increase in the motor vacuum, a cylinder, a piston reciprocal' in said cylinder and coupled with said air valve for positive movement therewith between closed and opened positions of said valve, said cylinder being in communication with the motor intake line for establishing a suction force in the cylinder of a predetermined magnitude acting on the piston in a direction to apply a closing force to the valve to maintain the valve closed against the opening force applied thereto by a vacuum of predetermined magnitude, the closing force applied by the piston being overcome by the opening force on the valve of a motor vacuum greater than the predetermined magnitude, whereby the valve moves with the piston to valve opened position, and means coupled with the motor throttle valve actuating mechanism for opening and closing said cylinder to communication with the motor intake line in accordance with the position of the motor throttle.

3. In combination with an internal combustion motor including the motor intake line, throttle valve and its actuating mechanism, an air valve for opening by the suction force of the motor vacuum to admit air to the motor intake line to prevent increase in motor vacuum, a spring continuously exerting a closing force on said valve of substantially constant magnitude to maintain the valve closed against a motor vacuum of predetermined magnitude, a cylinder, a piston reciprocal in said cylinder and coupled with said air valve for positive movement therewith between closed and opened positions of said valve, said cylinder being in communication with the motor intake for establishing a suction force in the cylinder of a predetermined magnitude.

- force applied to the valve of a vacuum up to a predetermined magnitude, the combined closing forces applied by the spring and piston being overcome by the opening force on the valve of a, motor vacuum greater than the predetermined magnitude whereby the valve moves with the piston to valve opened position, and means coupled with the motor throttle actuating mechanism for opening and closing said cylinder to communication with the motor intake in accordance with the position of the motor throttle.

I 4. In an internal combustion motora'throttle valve and its operating mechanism, an air valve for opening to admit air to the motor intake to prevent increase in motor vacuum, suctionoperated means embodying a cylinder and a' piston .35

'therein positively coupled with the air valve for applying a'closing force to the valve of a predetermined magnitude, a suction line connecting said cylinder with the motor intake whereby the motor vacuum creates a suction force in the cylinder to actuate said piston to apply the closing force to the Valve, a control valve in said suction line arranged so that in-maximum open'position only a predetermined maximum suction force, can be created in the cylinder irrespective-of the 5:15 maximum magnitude that may be attained by the motor vacuum, and means operatively coupling said control valve with the throttle valve operating mechanism so that the control valve is opened and closed in accordance with the position of said throttle valve. Y

5. In an internal combustion motor, an air valve mounted for opening to admit air to the motor intake to prevent increase in motor vacuum, yielding means continuously exerting a closing force on said valve of predetermined magnitude, said valve being subjected to the suction force of the motor vacuum acting on the valve in a direction to open the same when the vacuum attains a magnitude to exert a force on the valve to overcome said yielding means, suetion operated means embodying a cylinder and a piston therein positively coupled with the air valve for applying a closing force to the valve of a predetermined magnitude, a suction line connecting said cylinder with the motor intake whereby the motor vacuum creates a suction force in the cylinder to actuate said piston to apply a closing force to the valve in addition' to the closing force applied by said yielding means, a control valve in said suction line arranged so that in opened position only a suction force of a predetermined maximum can be created in the cylinder to act on said piston irrespective of the maximum magnitude that may be attained by the motor vacuum, and means for opening and closing said control valve to cause said suction operated means to apply closing force to or remove the same from the air valve.

6. In combination with an internal combustion motor, including the motor intake line and the motor throttle valve and its operating mechanism, a normally closed air valve adapted to be opened by the suction force of the motor intake vacuum acting thereon to admit air into the intake line to prevent increase of motor vacuum,means continuously applying a force to said air valve of a magnitude to maintain the same closed against the valve opening force of a predetermined maximum motor vacuum, means op- 60 erated by the motor vacuum and coupled with the air valve .for applying a closing force of 'a predetermined maximum magnitude to the air valve in addition to theforce applied by said first mentioned means to thereby maintain the valve as closed against a greater vacuum force of a-predetermined maximum magnitude, said air valve adapted to be opened against the combined closing forces of said means by a vacuum acting on the valve of greater magnitude than the prede- 70 termined maximum vacuum, and means coupled with said throttle valve mechanism for actuating said vacuum operated valve closing force applying means to render the latter inactive for a portion of the operating range of the throttle valve between a predetermined 'open position and maximum open position.

7. In an internal combustion motor, including an intake line and the motor throttle valve and operating mechanism, a normally closed valve by the motor vacuum for applying a closing force to the valve of a predetermined magnitude, said valve being maintained closed by the combined closing forces applied thereto by said means and being opened when the motor vacuum attains a magnitude to apply a suction force to the valve sufiicient to overcome said combined closing forces, and means operated by the throttle mechanism for rendering said valve connectedvacuum actuated means inactive or active in ac-' cordance with the'position of the motor throttle.

8. In an internal combustion motor, including the intake line thereof and the motor throttle valve and actuating mechanism for said valve,

a normally closed air valve for opening to admit air into the intake line to prevent increase in motor vacuum, said air valve being continuously subjected to the suction force of the motor vacuum acting thereon to open said valve, force means continuously applying a'closing force to 7 said valve of a predetermined magnitude to maintain the valve closed against a motor vac uum of a predetermined maximum magnitude acting on the valve to open the same,rmeansfor applying the suction force of the motor vacuum to said valve in a direction acting thereon to close the valve simultaneously with the application of the forces to the valve tending to open the same, and means coupled with and operated by v the throttle valve actuating mechanism for rendering said suction force applying means inactive at a predetermined position of said throttle valve whereby said force means then solely acts to maintain the valve closed against the continuously acting suction force applied to the valve in a direction to open the same by the motor vacuum. THOMAS CLARENCE MARSHALL. 

